>After every return from testing the form, when an error occurs the Data Environment is empty. I have 4 tables in my Data Environment [or had!]. The tables are views. I have many other forms in this project and they are not having the same problem.

I've had the same problem in VFP5 several times, and I thought it may be connected with some undocumented features of VPM5 that was in use at the time. The symptoms were the same, one and only that one form kept losing the DE. The workaround was to save the form after doing any changes and run it manually afterwards, i.e. not using the "Run form" option on the context menu, nor the Run button which appears on the toolbar. This has become a habit to me, and the error never reoccurred. I've seen the guys around me still doing it using the automatic save and run from the context menu, and they didn't complain about this for at least a year; it's probably been fixed in VFP6.